Subgrade vaults are widely used to provide internal enclosed regions where utility connections can be made and housed. Classic examples of such connections are the joiner of electrical and fiber optic cables used in street lighting, in telephone and communication systems, and water valves for residential communities and golf courses. These vaults are generally placed below grade of ground level with their upper surfaces at grade where loads from pedestrians and vehicles, as well as environmental factors such as the presence of precipitation and animals, are anticipated. Generally, the vaults will be used by municipalities, utility companies, homeowners, and other locations where longevity, durability, and affordability are important criteria.
Vault systems and devices are intended for access and interaction with trained professionals who, for example, need to service complex, dangerous, and/or valuable subgrade systems to maintain vital infrastructure. Accordingly, in addition for these devices and systems to withstand various forces and abuse due to environmental conditions, it is desirable to provide systems that allow for general ease of access to the appropriate individuals, while simultaneously preventing unauthorized access. A lid for providing access to an enclosed subgrade region must not only be structurally sound, but must be simple to remove and replace, while reliably holding the lid onto the body when access is not needed.
Subgrade storage systems generally contain and/or provide access to valuable components necessary in performing critical functions and/or with respect to monetary value. In part due to the high commodity prices of metals and other internal components, theft is an increasing problem which is not only expensive but extremely disruptive when communication, electrical or water service is discontinued. Furthermore, improperly secured or physically damaged subgrade systems may present hazardous conditions to passer-bys and professionals alike.
Prior art vaults comprise a lid or other feature to enclose a vault and protect the contents of the vault. The following references relate to the field of subgrade storage vaults and facilities and are hereby incorporated by reference in their entireties: U.S. Pat. No. 4,567,697 to Hahne; U.S. Pat. No. 6,772,566 to Machledt et al.; U.S. Pat. No. 6,899,240 to Dang et al.; U.S. Pat. No. 7,163,352 to Jurich et al.; U.S. Pat. No. 7,385,137 to Burke et al.; U.S. Pat. No. 7,467,910 to Lecuyer et al.; and U.S. Pat. No. 7,748,926 to Jurich et al.
One issue with prior art vaults is that the lid rests on a horizontal lip or seat of the vault, and thus, the lid is prone to deformation and other structural risks as weight is applied to the lid area. Subgrade vaults are often used in areas, for example sidewalks, where people walk on the lid. Since the lid rests on a horizontal lip or seat of the vault and the relative position between the lid and the horizontal lip or seat is not fixed or maintained, the center of the lid can deflect downward when a person steps on the lid or vehicles driving on the lid. In another scenario, prior art vaults are positioned in ground where shifting soils distort the shape of the side walls of the vault. Over time and repeated deflections and distortions, the lid may deform and become disengaged from the side walls of the vault and cause failure. Further, the ability of the lid to secure to the vault can become compromised, and any sensitive equipment and expensive commodities within the vault are exposed to damage or theft. Therefore, there is a long-felt but unmet need to provide a subgrade vault having features adapted to improve the structural integrity of the vault, and to provide a lid that does not become disengaged from the vault housing.